Fulvene compositions and polymers



United States Patent "ice 3,390,156 FULVENE COMPOSITIONS AND POLYMERS Marvin I. Hurwitz, Ellrins Park, Pa., and Donald M. Fenton, Anaheim, Calif., assignors to Rohm and Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Filed Oct. 11, 1963, Ser. No. 315,663 5 (Ilaims. (Cl. 260-3468) This invention deals wtih fulvenes, fulvene-containing resins and fulvene plastics.

The plastic industry has attempted to keep up with the challenge imposed by the opening up of new fields of endeavor and by broad extension in areas where generally more conventional materials had been relied upon. These developments, together with a general need to meet stricter and higher standards, have pointed out serious shortcomings in conventional resins. This has become particularly apparent in the field of unsaturated polyester resins cross-linked and thermoset with a polymerizable compound, such as one containing a CH =C group. A very serious problem confronting this area of the plastic industry is the extreme shrinkage experienced during the conversion of the polyester resin to the cross-linked plastic. During the curing cycle, when the plastic material is being formed by the cross-linking occurring between the unsaturated component in the linear polyester and the monomer having a CH =C group, a shrinkage in the overall dimensions of the plastic occurs which sometimes is as high as This is, of course, a very objectionable characteristic. This shrinkage causes objectionable stresses and strains within the plastic. These, in turn, tend to lead to the formation of cracks and creases, and breaks in the plastic structure. On the surface, such imperfections would be noticeable and the exposed surfaces of the plastic may lose their gloss and shine. As

another attendant drawback, the plastics then show a de crease in resistance to solvent impregnability. Internally, shrinkage also has serious consequences. The poor dimensional stability of such resins promotes weakening of the resins, lowering their rigidity and their fiexural strengths. As binders of laminated articles and in glassreinforced plastics, poor dimensional stability lowers adhesion properties. I

To these vexing problems, even the more astute workers in the art have not yet proposed an adequate and satisfactory solution.

The present invention provides new polymerizable polyester resins and polymerized cross-linked plastics of remarkable dimensional stability.

The polymerizable resinous compositions are a blend of an unsaturated polyester and a fulvene compound, chemically combined, in a Diels-Alder type addition, with the unsaturated component of the polyester. The polymerized composition is a cross-linked insoluble, infusible plastic of the polyester and the fulvene. The compositions exhibit minimal shrinkage and excellent dimensional stability. As a result, the invention provides plastics having a novel combination of advantageous properties. The plastics of the invention have increased strength properties because the volumes of high energy density, which occur in volumes contained in the stressed, conventional molecules of the polyester plastics, are minimized. The plastics of the invention provide for more homogeneously cast or constructed parts; therefore, they exhibit a minimum of surface stress with resulting minimum of crazing and cracking. Because fewer active sites for initiating deterioration and breakdown are available in the plastics of the invention, the products tend to be more resistant to hydrolytic, solvolytic and ultraviolet breakdown. In laminating and glass-reinforced plastic applications, the resins of the invention provide improved wetting of the surfaces of the materials treated and, therefore, they have 3,390,156 Patented June 25, 1968 better adhesive properties. The resins of the invention open new vistas to fabricators making it possible for them to set closer tolerances on the dimensions of their plastic finished products, making possible, for instance, the design and manufacture of plastic materials of more complicated design with narrow and/or thin dimensions.

The present invention provides a number of notable embodiments. One embodiment comprises a stable, yet polymerizable, resinous mixture of linear polyester with a fulvene, a potential cross-linker, which is in a Diels- Alder type of chemical combination with at least one of the ethylenic bonds in the unsaturated polyester backbone. One type of resinous mixture is substantially free of ethylenic unsaturation in the polyester backbone as a consequence of the fact that the fulvene is at least in equimolar proportion with the unsaturated component in the polyester. The fulvene component may be in excess of the unsaturated component of the polyester. In other types of resins, the proportion of fulvene is less than equimolar with respect to the unsaturated component of the polyester.

In such a case, the polyester resin is unsaturated to the extent of the molar difference between the unsaturated component of the polyester and the fulvene component. The resin is a useful composition of a viscous nature which is stable over extended periods of storage. Unlike conventional compositions of solutions of polyesters in copolymerizable ethylenically unsaturated compounds such as styrene, the resins of the invention do not need any inhibitor; although they already comprise, in the fulvene component, the potential copolymerizable crosslinker.

Another embodiment of the invention provides compositions comprising a polyester and a fulvene polymerized and cross-linked into an infusible and insoluble plastic.

An aspect of the above embodiment. is directed to a method for converting the Diels-Alder type resinous adduct product to the cross-linked, polymerized plastic which comprises heating the resin to within a temperature range Within which cross-linking between the fulvene and the unsaturated portions of the linear polyester occurs and below that at which the interpolymerization of the fulvene will take precedence over the cross-linking reaction. The conversion of the stable resin into the cross-linked plastic apparently goes through an intermediate stage during which a reversal of the Diels-Alder type adduct to the fulvene and the unsaturated polyester component takes place by a temporary dissociation of these components. The dissociation is apparently followed by a rearrangement of the bonds of the various components so that a cross-linked plastic product results in which two of the double bonds of the fulvene are cross-linked with the unsaturated components of the polyester backbone chain.

These features are quite unusual because in conventional resins which forms Diels-Alder type resinous adducts, such as the Knapp resins or their equivalent, no such dissociation is known to take place, and even if it were to take place, the dissociated components are incapable of cross-linking without the incorporation of a conventional cross-linker such as styrene.

Another embodiment of the invention provides for a new class of fulvenes which are especially useful in the resins and the plastic composition of the invention. A related aspect concerns a method for making these fulvenes by a condensation involving a compound bearing at least one carbonyl, 0 0, group with a cyclopentadiene component, in the presence of a basic catalyst. Another related useful aspect of the invention provides stable Diels-Alder adducts, simple di-Diels-Alder and poly-Diels-Alder adducts, of these fulvenes and suitable dienophiles. Another aspect of the invention provides useful polymer-s, i.e. the

homopolymers of these fulvenes and their copolymers with copolymerizable ethylenically unsaturated comonomers. These and other related embodiments are further described herein.

The fulvenes which may be employed in accordance with this invention may be represented by the formula In the nomenclature of these fulvenes, the carbon atoms are numbered as shown. For clarity, the fulvenes are considered as made up of two portions: (1) a cyclopentadienylidene portion which comprises carbons numbered 1 to and groups R to R and (2) a portion which includes carbons numbered 6 and R and R and which is herein designated as exocyclic because it is outside of the ring of carbon atoms numbered 1 to 5. This second portion of the ful-vene is derived from a carbonyl, C=O residue, i.e., it is a ketone or an aldehyde containing at least one carbonyl group free of its oxo, 0:, oxygen. Either one or both of R and R may be linked to R and/or R to form one or more cycles. This may arise when the second portion (2) contains more than one as two, three, or four, or more carbonyl residues.

A preferred method for making the fulvenes which are employed in this invention is a method which is further described below which comprises a condensation of a cyclopentadiene, or its equivalent, with a keto-carrying compound, such as an aldehyde or a ketone.

In Formula I,

(1) R and R selected individually, is a hydrogen atom or a hydrocarbon group which may, optionally, be substituted with inert, non-interfering substituents. Typical hydrocarbon groups are alkyl, aryl, alkaryl, and aralkyl;

(2) R to R selected individually, represent a hydrogen atom and/or R to R is a hydrocarbon group which may be in part or in toto substituted with non-interfering substituents, such as alkyl, aryl, alkoxy, carboxyl, halogens and the like. Generally, the total carbon atom content of these substituents does not exceed 12 to 20;

(3) One of R and R is a hydrogen atom or a hydrocarbon group defined under (1) and especially an alkyl group, while the other of R and R is linked with one of R and R to form a divalent alkylene chain, which together with the carbon atoms of the cyclopentadienylidene portion, form a cycloalkylene ring, generally containing 4 to 10 carbon atoms in the ring. The ring may be further substituted with alkyl substituents.

A further embodiment of the invention deals with a special group of fulvenes which may be represented by the formula la 1L4 The fulvenes of this first group may optionally have further substituents on the cyclopentadiene component. Of special interest are those in which the optional substituent is an alkyl or an alkylene group, especially a branched alkylene group, such as an alkylene group substituted by an alkyl group as its a-carbon atom. More readily available are those fulvenes in which the alkylene or alkyl substituents contain a maximum of 12 carbon atoms. Still within the first group are included those fulvenes in which one of R and R is a cycloalkylene group, generally containing 5 to 7 carbon atoms in the ring, which, optionally, may carry alkyl substituents to form a cycloalkylene grouping containing a total of 12 carbon atoms.

In a second group of fulvenes, (2) while both R and R are an aryl group of 6 to 14 carbon atoms, the cyclopentadiene component of the fulvene carries a branched alkylene group, generally not exceeding a content of 8 carbon atoms.

In a third group of fulvenes, (3), R and/or R is an alkylene group, straight or branched, with. ethylenic unsaturation located terminally. Generally, the carbon content of each R and R is a maximum of 18 carbon atoms.

In a fourth group of tulvenes (4), one of R and R is a hydrogen atom and the other of R and R is linked with one of R and R to form a cycloalkylene carbocycle. The cycloalkylene chain may contain 2 to 6 carbon atoms or more, and it may, optionally, be substituted with further alkyl substituents, generally having not more than 4 carbon atoms.

This special class of fulvenes is characterized by a number of valuable properties. When the 6-carbon atom of the fulvene is substituted with only one cobranched alkyl group, the reactivity of the fulvene appears to be optimum in the formation of the Diels-Alder adducts and in the polymerization reactions. This advantage appears further enhanced and was reflected in the polyester cross-linked products when these fulvenes possess alkyl, and especially branched alkenyl, substitution on the cyclopentadicnylidene portion. When the fulvenes have alkenyl with a terminal vinyl group on the cyclopentadiene portion and substitution free of acetylenic unsaturation on the sixth carbon atom, they appear more reactive in polymerization reactions with the attendant advantage of shorter curing cycle. The cycloalkylene chain may contain 2 to 6 car- When the fulvenes are disubstituted on the sixth carbon atom with an alkenyl group having vinyl unsaturation, again unexpected advantages are obtained in the plastic product. The polycyclic tulvenes in which the substitution on the sixth carbon atoms forms one or more rings by linking with one or more carbon atoms of the cyclopentadienylidene portion also appear to confer further advantages in the final resinous and plastic products.

Typical of these fulvenes are the following: 6-a-rnethylbutyl fulvene, 6-a-methylhcxyl fulvene, 6 amethyldodecyl fulvene, 6-isopropyl fulvene, 6-cyclohex-9-enyl fulvene, 6-cyclohex-8-enyl fulvene, 6-cyclopent-7-enyl fulvene, 6-cyclohept-8enyl fulvene, G-cyclo-(Z-mcthyl) hex-9-enyl fulvene, 3({f-mcthyl-d-pentenyl)-6-ot-methylbutyl fulvene, 3(fi-cthyl-a-hexenyl) 6 0 mcthylhexyl fulvene, 3-isopropenyl-6,6-diphenyl fulvenc, 3-isopropenyl-6,6-xylyl fulvene, 3-isopropenyl-6,61linaphthyl fulvene, 3-isobutenyl-6,6-diphenyl fulvene, 3-(ot-methyl) penyl-6,6-xylyl fulvene, 3-isopropenyl-6,6-.linaphthyl ful- 6-divinyl fulvene, 6,6-diisopr0penyl fulvene, 6,6-(y-heX- enyl) tulvene, 6-methyl-6-(y-butenyl) fulvene, 6-methyl- 6-vinyl fulvcne, 6,7-dihydroazulene, and the corresponding bicyclic fulvenes from glyoxal, malonaldehyde, succinaldehyde, adipaldehyde.

The fulvenes of the invention are prepared by a method which comprises reacting a compound carrying at least one carbonyl group, C 0, and which may be represented by the formula With a cyclopentadiene portion 0:0 lt I H (IV) preferably in the presence of a catalytic amount of a s 'l ypical of the carbonyl-carrying compounds are the following carbonyl compounds:

RCHO

wherein R is a straight chain or branched alkyl group, an aryl group, an alkaryl group, or an aralkyl group, preferably containing 1 to 18 carbon atoms. Typical are the following: acetaldehyde, propionaldehyde, n-butyralde' hyde, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde, n-caproaldehyde, n-heptaldehyde, stearaldehyde, cinnamaldehyde, p-tolualdehyde, and other substituted aldehydes, such as o-chlorobenzaldehyde, m-nitrobenzaldehyde, 2- intro-3,4,S-trimethoxybenzaldehyde, and the like.

Typical other carbonyl-carrying compounds are the ear bonyl compounds of the formula R COR wherein R and R selected independently, are alkyl, aryl, alkaryl, or aralkyl groups, preferably containing from 1 to 18 carbon atoms. Typical are the following: acetone, methyl ethyl ketone, methyl n-propyl ketone, diethyl ketone, hexanone-Z, hexanone-3, methyl tbutyl ketone, din-propyl ketone, diisopropyl ketone, diisobutyl ketone, din-arnyl ketone, stearone, diacetyl, acetylacetone, mesityl oxide, phorone, cyclohexauone, benzophenone, methyl propyl ketone, methyl hexyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl dodecyl ketone, methyl allyl ketone, methyl methallyl ketone, acetophenone, civetone, exaltone, p-nitroacetophenone, mchloroacetaphenone, p isopropylacetophenone, p-t-octylacetophenone, methyl naphthyl ketone, Z-acetylphenanthrene, 2-acetyll-naphthol, l-acetonaphthone Z-hydroxyeyclohexanone, cyclopentanone, cycloheptanone, p-t-butyl cyclohexanone, m-isopropylcyclohexanone, 3-methylcyclopentunone, whydrindone, ,8-hydrind0he, wtetralone, dtetralone, 6-methoxyu-tetralone, p-methoxyacetophenone, 4-butoxycarbonylcyclohexanone, 4-methoxycyclohexanone, 4-hydroxycyclohexanone, n-aminoacetophenone, p-dimethylamino-acetophenone, Z-trifiuoromethylacctophenone, p-methoxyacetophenone, methyl levulinate, butyl levulinate, ethyl ,B-methyllevulinate, l-hydrindon, 1- tetralone, and pinacolone. Also, there may be used ethyl acetoacetate mesitononitrile and the like.

The ketone-carrying compound is reacted with a compound 4 which is the cyclopentadiene portion of the fulvene. Typical of such cyclopentadienylidene residues are the following dienes:

cyclopentadiene,

1,5,5 -trimethyl-l,3-cyclopentadiene, l-benzyl 1,3-cyclopentadiene,

2-benzyl-1,3 -cyclopentadiene,

1,4-diphenyl-l ,3 -cyclopentadiene, 1-phenyl-4-p-tolyl-1,3-cyclopentadiene, 1-carbomethoxy-4,S,S-trimethyl-1,3-cyclopentadiene, Z-carbomethoxy-1,5,5-trimethyl-1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,3,5,5-tetramethyl-1,3-cyclohexadiene and 1,5 ,5,6-tetramethyl-1,3-cyclohexadiene.

The cyclopentadiene residue of the fulvene is the product of a Diels-Alder reaction, that is, the reaction of cyclodiene with an appropriate dienophile. Such reactions are well known and are described in Organic Reactions, vol. 4, page 60, for instance.

The temperature at which the reaction between the ketocarrying compound 3 and the cyclopentadiene com pound is carried out is not critical.

The reaction is generally exothermic with some variations in the degree of exothcrm generated being observed with different carbonyl compounds. As an overall range, about -20 to about C. is suitable. However, with the aldehydes, the reaction appears to be more vigorous and, for best yields, it may be preferable to apply means for moderating it.

For example, cooling means may be used when necessary to preferably keep the temperature in the range of 20 to 40 C. for the substituted aldehydes and in the range of 20 to 10 C. for the straight chain aldehydes.

The carbonyl compounds which are useful in the preparation of the fulvenes may have a single or a plurality of formyl or carbonyl functions; the compounds may have both formyl and keto functions; they may be substituted with other functional groups, inert in the present reactions. In the case of the ketones, their somewhat more sluggish reaction may be accelerated by applying heat ing or equivalent means to maintain the temperature in the preferred range of about 30 to 60 C. To favor best yields, it is advisable to keep the reaction temperature below the temperature at which the fulvenes will polymerize with themselves. This reaction, which would be competing with the formation of the fulvenes, is generally adequately minimized by maintaining the temperature below 120 0., preferably below 90 C., for the more reactive fulvenes. The order of addition of the compounds III and IV is not critical, but it is preferable to add the keto compound II to a mixture of the cyclopentadiene portion IV and the base catalyst in order to minimize the formation of byproducts that could occur in the situation where an aldehyde or a ketone and a base are pre-mixed. A solvent may be used, if desired, to facilitate handling the reactants, especially where one of them is not a liquid. Solvents that may be used include organic, inert solvents such as: oxygen containing solvents like others, acyclic or cyclic, as dimethyl ether, di-n-propyl ether, tetrahydrofuran, di-n-amylether, water, alcohols, aliphatic or aromatic, as methyl, ethyl, propyl, t-aryl, benzyl alcohols, and the like.

Theory requires a stoichiometric amount of reactants II and IV. But, if desired, there may be employed an excess of keto compound II such as a 10 to mole percent excess.

Any base may be employed to catalyze the reaction between 11 and IV. Any amount that promotes the speed of the reaction is adequate for the purpose. Such a catalytic amount may be a trace, such as 0.01% per mole of reactant, or there may be used amounts as high as 0.25 to 1% or more. Advisably, the amount of catalyst is adjusted to the reactivity of the reactant II to give a speedy, yet controllable, reaction.

The reaction between the carbonyl-carrying compound and the cyclopentadienylidene residue is carried out in the presence of a base. Typical bases that may be employed are the following: alkali metals and the alkaline earth metals, such as lithium, sodium, potassium, strontium, barium and calcium; alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide; their oxides such as lithium oxide, sodium oxide, and potassium oxide; alkali metal lower alkoxides such as lithium butoxide, sodium methoxide, sodium-t-butoxide, and potassium ethoxide; alkali metal hydrides, such as sodium hydride and potassium hydride; alkali metal amides such as sodium amide, lithium amide, potassium amide; alkali metal lower alkyls, alkenyls and alkynyls, such as methyl lithium, ethyl sodium, butyl potassium, allyl sodium, and butenyl potassium; phenylalkyl alkali metals such as benzyl sodium, phenylisopropyl potassium, sodium phenylacetylide and alkali metal aromatic such as phenyl sodium, phenyl lithium and phenyl potassium, phenyl butyl sodium; Alfin catalysts, which are commercial mixtures of alkali metal alkenyls and alkali metal alkenoxides, such as allyl sodium with sodium allyloxide and butenyl potassium with sodium butenyloxide, and quaternary ammonium bases such as trimethylbenzylammonium hydroxide and dimethyldibenzylammonium hydroxide and the corresponding alkoxides, such as trimethylbenzylammonium butoxide, choline methoxide, and the like.

Other embodiments of this invention are the Diels-Alder adducts of the fulvene with suitable dienophiles. Any dienophile is suitable for forming the adduct. Following the general pattern of the reaction, the fulvene will add to the 1,4-position of the conjugated diene system in the dienophile. A great variety of dienophiles are suitable for the formation of the adducts. For the formation of simple Diels-Alder adducts, the fulvene and the dienophile are used in equimolar proportions. The double Diels-Alder adducts are obtained from 2 moles of fulvene for each mole of dienophile.

The Diels-Alder adducts are prepared by reacting the fulvene with a dienophile. Generally, the reaction is carried out at room temperature, that is, in the range of 20 to 50 C., 'but it may be carried out in the range from about C. to 100 C. with suitable adjustments in the reactivity of the respective reactants. If desired, an inert solvent, such as aromatic or paraflinic hydrocarbons, such as benzene or isooctane or ethers such as tetra'hydrofuran may be employed to dissolve the reactants and/ or to moderate the reaction. Under such conditions, a quantitative yield of the adduct often separates from the solution in nearly pure form. Adducts of the lesser reactive dienes and fulvenes form adducts when solutions of the components are refluxed at elevated temperatures.

Typical dienophiles include the following: maleic anhydride, methyl acrylate, butyl acrylate, methyl methacrylate, and other acrylates and methacrylates, such as dimethyl acetylene dicarboxylate, dimethyl fumarate, dioctyl fumarate, methacrylic acid, acrylic acid, fumaric acid, dimethyl maleate, dimethyl fumarate, diisobutyl maleate, fumaryl chloride, citraconic anhydride, methyl fumaric acid, and other similar dienes.

The adducts of the fulvenes and the dienophiles are free-flowing liquids which are non-polymeric. They are useful in the formation of polyester resins along with or separately from the fulvene monomers. The Diels-Alder adducts of the invention are of particular value in decreasing the viscosity of the polymeric fulvene resin by blending the adduct, in any desired proportion, with the polyester resin. Ideally, the constituents of the adducts are so selected that the decomposition of the Diels-Alder adduct and the copolymerization of the resulting diene and dienophile occur at about the same temperature, or within a temperature range of 10 C. of each other, as the similar reactions of the Diels-Alder adduct of the fulvene and the unsaturated polyester occur.

Another embodiment of the invention provides polymers and copolymers of the fulvenes, the Diels-Alder adducts, of the invention. Polymerization (homopolymerization and copolymerization with other monoethylenically unsaturated polymerizable compounds) of the fulvene is preferably effectuated in the presence of a free radical catalyst or initiator.

As useful unsaturated compounds for forming the copolyrners there may be used acrylic acid, methacrylic acid, esters of acrylic acid or methacrylic acid and monohydric alcohols such as methyl, ethyl, butyl, octyl, dodecyl, cyclohexyl, allyl, rnethallyl, undecenyl, cyanoethyl, dimethylaminoethyl, and the like; esters of itaconic acid and similar alcohols; esters from maleic, fumaric or citraconic acids, and likewise similar alcohols; vinyl esters of carboxylic acids such as acetic, propionic, butyric, and the like; vinyloxyalkyl esters such as vinyloxyethyl acetate; vinyl ethers such as ethyl vinyl ether, butyl vinyl ether, octyl vinyl ether, allyl vinyl ether, hydroxyethyl vinyl ether, aminoethyl vinyl ether, nminopropyl vinyl ether, dimethylaminoethyl vinyl ether. vinyloxycthoxycthanol, vinyloxypropoxyethanol; inetlmcrylonitrile or acrylonitrile; acrylamide, or methacrylamide, and N-substituted amides of these types; vinyl chloride, vinyl bromide, vinylidene chloride, l-chloro-l-luoroethylene, or ethylene; l-acetoxy-1,3-butadiene; styrene, or divinylbenzene; ethylene diacrylate or dimethacrylate, bis(vinoxyethy1) urea, vinoxyethyl acrylate, vinoxypropyl acrylate. Where two polymerizable vinylidene groups occur in the same molecule, as in compounds toward the end of the above list, cross-linking results where more than one to two percent thereof is used in forming the copolymer.

In accordance with the, invention, the unsaturated polyester component of the blend of the unsaturated polyester and the fulvene and of the polymerized crosslinked composition is any type of polyester of the unsaturated type. The constituent of the particular unsaturated polyester is immaterial. Numerous references are found in the literature (such as in Polymer Processes, vol. X, Chapter 17, and Polyesters and Their Applications by Bjorksten, Reinhold, 1956, and in patent references. Illustrative examples of the components which may be used in the preparation of the unsaturated polyester component which is used in conjunction with the fulvene of the invention, the following acids, alcohols, and mixture of acids, are illustrative.

Aliphatic polyhydric alcOh0ls.-Ethylene glycol, propylene glycol, trimethylene glycol, triethylene glycol, pentaethylene glycol, polyethylene glycol, 1,4 butanediol, diethyleneglycol, dipropylene glycol, 2,2-dimethyl-1,3- propanediol, hexamethylene glycol.

Aromatic polyhydrz'c alc0h0ls.Xylylene alcohols, ethyl resorcinol, propyl resorcinol, 2,4-dimethyl resorcinol, 3,6-dimethyl-1,2,4-benzenetriol, ethyl pyrogallol, Z-methyl-1,4-dihydroxy naphthalene, 3 methyl-1,4,5- naphthalenetriol, dimethylol toluene, dimethylol xylene, bis hydroxy ethyl or bis hydroxy propyl ethers of resorcinol, catechol, hydroquinone, 1,5-dihydroxynaphthalene, 4,4 isopropylidene bis phenol, etc.

Unsaturated dibasic acids and anhydrideS.Maleic acid, ethyl maleic acid, maleic anhydride, citraconic acid, muconic acid, fumaric acid, aconitic acid, mesaconic acid, itaconic acid.

Saturated dibasic acids.Adipic acid, azelaic acid, sebacic acid, dodecyl succinic acid, succinic acid, tetrachlorophthalic anhydride, hexahydrophthalic anhydride, l,4,5,6,7,7-hexachlorobicyclo(2.2.1)-5-heptane 2,3 dicarboxylic anhydride, malic acid and citric acid.

In addition to the foregoing dibasic acids and anhydrides, phthalic anhydride may be also employed. The polyesters preferred in accordance with the invention are those obtained by esterifying an unsaturated polybasic acid with a polyhydric alcohol. A fraction of the acid may be replaced by a saturated polybasic acid.

The proportions of the unsaturated polybasic acids, chlorinated derivatives or anhydrides thereof, or mixtures of saturated and unsaturated polycarboxylic acid with polyhydric alcohols, are not critical, and the proportions may 'be varied to any extent as long as a resinous polyester, preferably having an acid number below 60 is obtained. Polyesters having an acid number between about 5 and 50 are preferred.

The foregoing formulations are condensed by the usual polyester condensation procedure until the acid number is below 50. The reaction mixture is then cooled, and an inhibitor such as hydroquinone, resorcinol, pyrogallol, aniline, phenylene diamines, 'benzaldehyde and the like may be employed. The amount may range in the order of 0.1 to 10% by weight of the resin.

The proportion of fulvene which is employed in conjunction with the unsaturated polyester may range from 5 to 200% by weight of the unsaturated resin. For practical purposes, it has been found that 20 to by weight of the resin is a desirable proportion. Stated in molar amounts, unexpected desirable properties are obtained when the fulvene is in stoichiometrie an'tonnt with respect to the unsaturated fraction of the polyester. An excess of the fulvene over the unsaturated fraction of the polyester gives softer products, whereas amounts less than stoichiometric amounts with respect to the unsaturated fraction of the polyester gives products which are hard, rigid. If desired, a proportion, such as to 50% monomer, of the fulvene may be replaced by other monomers copolymerizable with the unsaturated polyester, such monomers being illustratively styrene, vinyl toluene, acrylonitrile, diallyl phthalate, methyl methacrylate, ethyl acrylate, and the like. Sometimes, the replacement of part of the fulvene by another copolymerizable monomer is desirable when a smaller proportion of the fulvene is sufficient to give the desired properties.

The polyester resin containing the cross-linking agent or mixtures thereof is cured by the addition of the usual curing catalyst which includes organic peroxides, peracids, hydroperoxides, and the like. Compounds of this type include benzoyl peroxide, lauroyl peroxide, tertiary butyl perbenzoate, 1,1-hydroperoxy diglycol, hexyl peroxide, methyl ethyl ketone peroxide, tertiary butyl peroxide and the like.

The cured polyester products of the invention are suited for any application where polyesters are used. They are especially suited for structural applications where shrinkage becomes an important element, such as in automobile bodies, luggage and reinforced fiberglas bodies. Also, they may be used for numerous other applications where other polyesters are useful, such as in adhesives, coating compositions, for wood, ll'IlGiHlS, plastics, or in the treatment of fibrous materials, such as paper, cloth, non-woven fabrics, as impregnating agents for fibrous materials, as assistants in dyeing and the like.

Example I PREPARATION OF FULVENES To a three-necked S-liter flask, equipped with a nitrogen inlet tube, reflux condenser, thermometer and dropping funnel, and mechanical stirrer, is added a solution of 383 parts of potassium hydroxide in 1380 ml. of methanol and 764.5 parts of cyclopentadiene, freshly distilled and stored at Dry Ice acetone temperature. The solution turns a red brown and is allowed to warm to 5 C., at which time 1130 parts of Z-methylpentaldehyde is slowly added. The temperature slowly climbs to 26 C. and at this point the reaction vessel is immersed in an ice bath to control the exothermic reaction, and the remainder of the aldehyde is added so that the temperature never exceeds 26 C. Total addition time is 2 hours and the dark mixture is allowed to stir for an additional one /2 hour at room temperature. The mixture is cooled in an ice bath and neutralizes with glacial acetic acid and an additional 200 ml. of 1 N hydrochloric acid is added. After standing over the weekend, the dark red organic layer is separated from the aqueous layer. The organic layer is washed with water, dried over magnesium sulfate, concentrated under aspirator pressure at room temperature and distilled. The fraction boiling at 40-48 C./0.5 mm. is collected, 896.7 parts or a 53.5% yield of 2-fulvenylpentane, 11 1.4997.

In the following examples, the general procedure of Example I is followed, the reactants and the variables being set forth.

Example 2 To 384 parts of cyclopentadiene in a solution of 244 parts of potassium hydroxide in 500 parts of tetrahydrofuran, there is added 244 parts of isobutyraldehyde. The reaction is maintained at 35 C. The product is isolated: it is 6-isopropylfulvene, 11 1.5046, boiling point 2829 C./ 0.2 mm.

Example 3 There are reacted 500 parts of tetrahydrofuran with 86 parts of cyclopentadiene. The reaction temperature is maintained at 30 C. The product which is isolated is 4- fulvenylcyclohexene, n 1.5514, boiling point 76 C./ 1.5 mm.

Example 4 There are reacted 100 parts of acetone and 66 parts of cyclopentadiene in the presence of 20 parts of sodium hydroxide. The temperature is maintained at C. The product which is isolated is 3-isopropenyl-6,6-dimethylfulvene, n 1.5378, boiling point 47-50 C./1.25 mm.

Example 5 There are reacted 44 parts of di-o butenylketone in the presence of 10 parts of potassium hydroxide in 200- parts of tetrahydrofuran with 53 parts of cyclopentadiene. The reaction is maintained at 65 C. The product which is isolated is 6,6-di(MbutenyDfulvene, 11 1.5336, boiling point 73 C./O.25 mm.

Example 6 There are reacted 800 parts of a 25% aqueous solution of glutaraldehyde in the presence of 50 parts of potassium hydroxide in a solution in 200 parts of water-ethanol with 140 parts of cyclopentadiene. The temperature is maintained at 35 C. The product which is isolated is 6,7- dihydroazulene. Its boiling point is 40 C./2.5 mm.

Example 7 PREPARATION OF DIELS-ALDER ADDUCTS Example 9 To 50 parts of 2-fulvenylpentane and 40 parts of methyl acrylate, there are added 150 parts of xylene and 0.5 part of hydroquinone. The yellow solution is refluxed under nitrogen for 6 hours. The Diels-Alder adduct product is distilled. It has a boiling point of -87 C./0.15 mm, 11 1.4794.

The following Table I provides examples of Diels-Alder adducts of various fulvenes with suitable dienophiles. Examples 1021 show simple Diels-Alder adducts, the addition product of 1 mole of diene and 1 mole of dienophile.

TABLE I Example Fulvene Dienophile Boiling Point or Refractive Melting Point Index 25 C.

2-fulveny1pentane. Methyl acrylate 8587 C./0.15 mm.. 1. 4794 Methyl methacrylate 43? C./0.7 mm... 1. 4764 Maleie anhydride Dimethyl acetylenedicarboxylate Ethyl acrylat-efin;2

19-: do .1 Dimethyl fumarate 20 3-isopropenyl-6,6-dimethylfulvene.. Dimethyl acetylenedicarboxylate -170 C./0.5 mm... 1 5282 21 5-isobutyenyhfi methylfulvene do 150180 C./0.4 mm... 1 6252 3,390,156 1 l l 2 The use of two moles of the fulvene with one mole of Example 34 dienophile gives the double Diels-Alder adduct. Examples 1 c 22 to 25 show such typical double Diels-Alder adducts. Llkewlse cop 0137mm of 2 fulvenyipentane 1nd d1 TABLE II I l e 1 Dieno hile Boiling Point or Melting Refractive Examp e Fu V 1 e p Point Index 25 C.

Methyl aorylate 1.5083 Methyl methacrylato 1 5085 Azo-bis-isobutyronitr 25: "do Ethyl acrylatc 1-5186 Further Diels-Alder adducts are prepared from the remethyl fumarate is prepared having an average molecspective diene and dienophile to give the products listed ular weight of about 534. m Tabb: HI. TABLE III EXamplB 35 Fulvene: Likewise a co ol mer of Z-fulven l eltane and di Dimethylfulvene Dioctyl fumarate. meth 1 t l 1 f f 34 6,6-pentamethylenefulvene Dimethyl fumarate. y eae avmg a mo ecu ar Welg 0 1S 6-hexyl-6-methylfulvene Maleic anhydride. prepare Do Dimethylfumarate. Example 36 D0 Melh'flcryllc acld- Likewise, a copolymer of 2-fulvenylpentane and butyl D0 Acryhc acldacrylate having an average molecular weight of 836 is 2-fulvenylpentane Maleic anhydride. preparecp Do Dimethyl fumarate. Example 37 Do Dioctyl fumaraie. Do Methacrylic acid. Likewise, a copolymer of 6-heXyl-6-methylfulvene and Do Acrylic acid. im hyl fumarate having a molecular weight of 739 to -isopropylfulvene Methacrylic acid. 107 i prepared.

Do Dioctyl fumarate. Example 38 Do Dimethyl fumarate. D0 Maieic anhydride A p lym r of a Diels-Alder adduct 18 obtained by adding to 5 parts of the Diels-Alder adduct of 6,6-di- EXamP16 26 methylfulvene and maleic anhydride, exo-7-isopropeny1- POLYMERIZATION OF PULVENES bicyclo(2.2.1)hept-5-ene-2,3-dicarboxylic anhydride, a

catalytic amount of benzoyl peroxide. The mixture is heated to 170 C., an orange oil is formed which turns into an orange glass on cooling It is soluble in chloroform and has a softening point above 250 C. (from acetone). Its molecular weight is about 699.

To 6 parts of 2-fulvenylpentane there is added 0.4 part of a 50% solution of benzoylperoxide in dibutyl phthalate. The yellow liquid is sealed from the air and heated to a maximum temperature of 140 C. for one hour to give a very viscous red liquid of a molecular weight of 500: 10.

Example 39 Likewise, the polymer prepared from 6-pheny1fulvene To a 3'necked Miter flask, equipped with an addition b 1 roxide had a avem e molecular Wei ht tunnel, mechanical stirrer, thermo-couple well, nitrogen 81 53? 6 n g g inlet, and reflux condenser, there are added 400 parts of an unsaturated polyester, a poly(dipropylene fu- Example 27 Example 28 v marate), heatm is started and at about 80 C. stirring Like/W156, the p p p f from 6i6'ulmethylful' is initiated, nitrogen being flushed throughout. To the V6116 had a 111016611131" Welght 0f J23i8- stirred polyester, there are added 138 parts of 2-fulvenylpentane containing 0.1 part of quinone over a one hour Example 29 .Likewise a polymer pregared from 66di(A4buteny1)' i or iii a dt litionail hn e h zili 1 1 501. i k v i ho ii s bl eiifi Z f ih fuivene had an average Welght of 946:5- unsaturated polyester and the fulvene compounds, chem- E l 30 ically combined in a Diels-Alder type addition, is obtained.

Increasing the proportion of the fulvenes over the stoichiometric amount of unsaturation in the polyester Example 31 gives stable poly Diels-Alder blends which are less vis- To 50 parts of dimethyl fumarate there are added 50 cons parts of 2-fulvenylpentane and 200 parts of xylene. The castmgs are prepared from the DlelsAlder blends of mixture is refluxed and a total of 0.420 part of di-t-butylg i g by h qj f ig i peroxide in 20 parts of Xylene is added over an 8 hour 6 cross m mg reac Ion Occurnng W1 m e period. The solution is further refluxed and mechanically i g l g to L E? products are stirred for an additional 18 hours under nitrogen. The E 9: 9 at t g E are comorange solution is concentrated under reduced pressure to P e e y u e m wa exam 6 GT0 acetone give, after distillation of unreacted materials, a polymer and'acetomtnle of a molecular weight of 534:5.

Example 32 The poly Diels-Alder adduct of the unsaturated polyester and the fulvene prepared in Example 39 are crosslinked by heating the viscous yellow blend for a 24 hour period in a polyester curing cycle from 50 to C.

Likewise, a polymer prepared from 4-fulvenylcyclohexene had an average molecular weight of 480:4. 55

Example 40 Likewise, a copolymer is prepared from 2-fulvenylpentane and styrene. Its average molecular weight is about Example 33 and back again. A yellow glass is obtained.

Other iulvene resins are prepared from various un- Likewise, a copolymer is prepared from 2-iulvcuylsaturated polyester resins and other typical fulvenes of pentane and methyl methacrylate. Its molecular weight the invention to give the Diels-Alder adduct blend and is about 539. 7 subsequently upon heating the cross-linked resin. Typical of such polyester resins that are prepared are the followform a cycloalkylene carbocycle having 2 to 6 carmg, the proportion of fulvenes to polyester resin being bon atoms While the other substrtuent of R to R expressed on a weight ratio basis. that is not llnked to one of R to R is a hydrogen TABLE IV Fulvene/ Example Polyester Fulvene Polyester, Description Weight Ratio 41 Poly(dipropylenefumarate) Fulvenylpentane 41/59 Orange glass. 42.- .....do ..do 50/ 50 Vicous orange liquid. 43.. .do 60/40 Semi-viscous orange liquid. 44.. Poly(propylenephthalatet'umarate) 29/71 Orange glass. 45-. do 40/60 Do. 46 .do .do 50/50 Viscous orange liquid. 47.- Poly(dipropy1enelumarate) 6-isopropyliulvene 36/ 63 Very viscous yellow liquid. 48.- .do o 50/50 Viscous orange liquid. 49.. .do 59/41 Orange liquid. 50.- Poly(propylenephthalatetumarate) /75 Yellow glass. 51.. do 40/ 60 Orange glass. 52.- 00/40 Viscous orange liquid. 53.. 33/67 Yellow glass. 54.- 40/60 Do. 55.- 50/50 Orange viscous liquid. 56.- 23/77 Yellow glass. 57.- 40/60 Do. 58.- 11 50/50 Viscous yellow liquid. 59 6 33/67 Yellow glass. 60 d 40/60 Yellow orange glass. 61 do ..do 50/50 Viscous orange liquid.

TABLE V.POLYESTER RESIN Ex. Unsaturated Unsaturated Saturated Acid Component Glycol Component Fulveue Component No. Anhydride Component Acid Component 62..... (19) Maleic (28) Adipie (29) Propylene (24)6-phenylfu1vene. (16) Maleie (33) Sebacic. (35) Dietnylene (16) G-phenyltulvene. 64..... (30) Mesacomc acid (30) Dipropyle (41) 6,6-di(N-butenyl-iulvenc). 65 (10) Mel (21) Dipropylene (59) 6,trdi(N-butenyHulvene). 66... (16) Maleie (43) Dipropylene (21) Mulvenylcyclonexane. 67... (29) Maleie i g g gg gigfii }-(40) 4-iulvenyl'eyclohexane.

l (33) Hexaincthylene.v (40) G-isobutenyl-G-methylfulvene.

(54) Dipropylene (7) fi-isobutenyl-G-methyllulvene.

(35) Dietnylene.- (18) 3-isopropenyl-6i,6-dimethylfulvene. (19) Ethylene--. (35) 3isopropenyl-(l,ti dimethyliulvene. (33) Propylene (7) oedimetnylfulvene.

(22) Ethylene.-. (37) (3.6-dimetuyliulvene.

) Azelaic (27) 1,3-butylene. (23) fi-isopropyllulvene.

08....- (27) Maleic 69 ...1 (1o) Maleic Mal 75"... (17) Fumarie ac (24) 2,5-endomethy1ene (40) pXylylene "I (19) 6,7 dihydroazu1cne.

hexahydrophthalie anhydride. 7e..." (18) Maleic (27 Phthalic Anhydride .{g igmgg 32 G'methyl-EmeiryIlulvene.

N OrE.-In parentheses, there is given the mole percent of each component in the polyester resin.

We claim: atom, with at least one mole of a dienophile selected 1. A Diels-Alder adduct comprising the reaction prodfrom the group consisting of methyl acrylate, ethyl net of one mole of a fulvene of the formula acrylate, butyl acrylate, methyl methacrylate, di-

methyl acetylene, dicarboxylate, maleic anhydride, R2 C Rl itaconic anhydride, methacrylic acid, acrylic acid, 0 dimethyl fumarate, dioctyl fumarate, fumaric acid, C R1l dimethyl maleate, diisobutyl maleate, fumaryl chloride, methylfumaric acid, and azo-bis-isobutyroni- 5O trile. R B 2. A Diels-Alder adduct comprising the reaction prodnet of one mole of -a-methylbutylfulvene with at least one mole of a dienophile selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, dimethyl acetylene, dicarboxylate, maleic anhydride, itaconic anhydride, methacrylic acid, acrylic acid, dimethyl fumarate, diocty'l fumarate, fumaric acid, dimethyl maleate, diisobutyl maleate, fumaryl chloride, methylfumaric acid, and azo-bis-isobntyrin which the substituents R and R are selected from the group consisting of (1) an alkyl group substituted on its a-carbon by an alkyl group having no more than 4 carbon atoms; (2) a cycloalkylene group having 5 to 7 carbon atoms in the ring while the other substituent of R and R is a hydrogen atom;

while under both classes 1) and (2) above, R

6 0 onitrile. g h tjdrh e a th r ri g li y ief gr ui ig gfi 3. The Diels-Alder adduct of claim 2 and maleic anhydride. is??? jg ifii g gg gg i 2 13:3212? 4. The Diels-Alder adduct of claim 2 and methyl acrylate.

(3) sg ggsg of 6 to 14 carbon a toms while one 5. The Diels-Alder adduct of claim 2 and methyl methlate of R to R 15 a branched alkylene group; acry n (4) an alkylene group having a maximum of 18 car- References Clted hon atoms and having a terminal ethylenic unsatura- UNITED STATES PATENTS and R3 to R5 is a g n tom and 2,745,844 5/1966 Dazzi 260 3468 (5) a hydrogen atom while one of the other substitu- 7O ents of R and R is linked with one of R to R t NICHOLAS S. RIZZO, Primary Examiner. 

1. A DIELS-ALDER ADDUCT COMPRISING THE REACTION PRODUCT OF ONE MOLE OF A FULVENE OF THE FORMULA
 3. THE DIELS-ALDER ADDUCT OF CLAIM 2 AND MALEIC ANHYDRIDE. 